As is well-known, air conditioning units are part of heating, ventilation, and air conditioning (“HVAC”) systems in buildings. Air conditioning systems have a number of air vents and operate by drawing in air for cooling via a return or intake air duct. The air drawn in via the intake air intake and directed toward a filter that filters out undesired particles from air flow in order to maintain air quality. The air is then run through a heat exchange device such as a compressor to output filtered and cooled air. However, a filter may affect the operation of an air conditioning unit via the flow rate of the air input to the system. For example, a filter that is saturated with trapped particles can impede air flow thus requiring greater power to operate and or restricting the amount of air that can be cooled.
For larger industrial HVAC systems, sensors are built into the HVAC system to provide alerts when clogged filters begin to impede operations of the system. However, many air conditioning systems are smaller scale and do not include sensors that detect the state of the filters. For example, in air conditioning systems for home use such as a window mounted air conditioning unit, no filter sensor is typically provided. Currently, it is difficult to determine whether a filter is impeding the operation of such an air conditioning unit and therefore must be cleaned or replaced. This is especially the case for smaller scale air conditioning units where cleaning or replacement of the filter is often ignored. Thus, energy efficiency as well as cooling capability is decreased as operation continues of the air conditioning unit and the filter traps more particles.
Thus, there is a need for a sensing device that will indicate when the filter on a specific air handling system is dirty and needs to be changed or cleaned. There is also a need for a device that is portable and may be employed by a user who does not have an internal air handling control that can monitor the condition of the filter in an air conditioning system. There is also a need for a device that provides the user with a precise indication of the condition of the filter on an air conditioning unit. There is a further need for a device that will not sound at night or other undesirable times when the user would not want to be disturbed if a filter is clogged.